A retrospective study of intra-oral salivary gland tumors from Thailand

Objectives: To determine the relative frequency and distribution of various types of intra-oral salivary gland tumors (ISGT) in the Thai population and to provide data for comparison with other studies. Materials and Methods: The files of the Department of Oral Pathology, Faculty of Dentistry, Chulalongkorn University from 1969-2007 were searched for ISGT. Histopathological slides were reviewed and reclassified according to the 1991 WHO Histological Typing of Salivary Gland Tumors. The age, gender, race and anatomical distribution of the tumors were collected from the patients' records. Results: Of the 16,358 accessioned cases, 311 cases (1.90%) were diagnosed as tumors belonging to a group of ISGT. One hundred and forty seven cases (47.27%) were benign tumors, while 164 cases (52.73%) were malignant tumors. The mean age of the patients ± SD = 41.57 ± 16.65 years. Females outnumbered male patients by a ratio of M:F = 1:1.38. Almost all except one patient were Thais. The top 5 most common ISGT were pleomophic adenoma (42.76%;n=133) followed by mucoepidermoid carcinoma (22.83%;n=71), adenoid cystic carcinoma (18.32%;n=57), adenocarcinoma (9.33%;n=29), and basal cell adenoma (2.89%;n=9), respectively. The majority of cases occurred in the palate followed by alveolar mucosa and intra-bony locations, respectively. Conclusions: Pleomorphic adenoma is the most common ISGT and the most common benign ISGT, while mucoepidermoid carcinoma is the most common malignant ISGT. ISGT in Thailand elicit similar trend as in previous studies with only minor differences such as the ranking of some tumors, the higher incidence of intra-bony location and the lower incidence of polymorphous low-grade adenocarcinoma.